Grasp point optimization by online exploration of unknown object surface

2013 IEEE/RSJ International Conference on Intelligent Robots and Systems

et al. 2013

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Abstract-We propose a feedback-based solution for the accurate manipulation of an unknown object in hand. This method does not explicitly take the friction and surface geometry of the manipulated object into consideration for the controller design, but employs a fast feedback loop based on visual and tactile feedback to perform robust manipulation even in the presence of unexpected slippage or rolling.At every control step, fingertip motions are computed to realize the intended object relocation, employing a composite position/force controller. Subsequently inverse hand kinematics is employed to retrieve joint-level motions, which are implemented on the robot with a position servo loop.We evaluate our method on two KUKA robot arms, each equipped with a tactile sensor array as end-effectors to perform the object manipulation task. The experimental results show the feasibility of our proposed method, even in presence of slippage or external disturbances.

Section: Discussionmentioning

confidence: 99%

“…The selected finger actively explores the object's surface to find a new optimal grasp configuration. In our previous work, we have employed physics-based simulation to show the feasibility of this approach [4]. The present paper will focus on an evaluation of the local manipulation controller on a real robot.…”

Section: Introductionmentioning

confidence: 99%

Integrating vision, haptics and proprioception into a feedback controller for in-hand manipulation of unknown objects

Elbrechter

2013 IEEE/RSJ International Conference on Intelligent Robots and Systems

et al. 2013

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“…We have shown previously, that we can autonomously find and follow the gradient direction of an arbitrarily chosen cost function, e.g. maximizing grasp stability and manipulability [11]. Here, we assume that the desired contact points are available on the object which we should servo to.…”

Section: Visuo-tactile-servoing Control Schemementioning

confidence: 99%

“…In the subsequent subsections we will outline four exemplary visual-servoing control schemes that are representative examples of the two interaction phases described in the introduction section: 1) Align and Approach the fingertips to the object center and approach the object to establish proper contact, 2) Maintain and Adjust sliding fingers across the object surface in order to reach desired contact points or to improve grasp stability as demonstrated before [11], 3) In-Hand Manipulation of the object 4) Exploration of the object's surface and acquiring a tactile point cloud. These actions are also shown in the accompanying video.…”

Section: Visuo-tactile-servoing Control Schemementioning

confidence: 99%

A visuo-tactile control framework for manipulation and exploration of unknown objects

2015 IEEE-RAS 15th International Conference on Humanoid Robots (Humanoids)

Ritter

2015

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Abstract-We present a novel hierarchical control framework that unifies our previous work on tactile-servoing with visual-servoing approaches to allow for robust manipulation and exploration of unknown objects, including -but not limited to -robust grasping, online grasp optimization, in-hand manipulation, and exploration of object surfaces.The framework is divided into three layers: a joint-level layer, a tactile servoing layer, and a visual servoing layer. While the middle layer provides "blind" surface exploration skills, maintaining desired contact patterns, the visual layer monitors and controls the actual object pose providing high-level fingertip motion commands that are merged with the tactile-servoing control commands.We illustrate the efficiency of the proposed framework using a series of manipulation actions performed with two KUKA LWR arms equipped with a tactile sensor array as a "sensitive fingertip". The two considered objects are unknown to the robot, i.e. neither shape nor friction properties are available.

“…Tactile servoing includes important tasks like sliding a finger tip along an object's surface, tracking specific surface structures like ridges, searching for distinctive tactile patterns, or exploring the object shape by groping. Most of these tasks are essential for both in-hand object manipulation [7], and haptic object identification [8].…”

Section: Introductionmentioning

confidence: 99%

Grasping and Manipulation of Unknown Objects Based on Visual and Tactile Feedback

Motion and Operation Planning of Robotic Systems

2015

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The sense of touch allows humans and higher animals to perform coordinated and efficient interactions within their environment. Recently, tactile sensor arrays providing high force, spatial, and temporal resolution became available for robotics, which allows us to consider new control strategies to exploit this important and valuable sensory channel for grasping and manipulation tasks. Successful dexterous manipulation strongly depends on tight feedback loops integrating proprioceptive, visual, and tactile feedback. We introduce a framework for tactile servoing that can realize specific tactile interaction patterns, for example to establish and maintain contact (grasping) or to explore and manipulate objects. We demonstrate and evaluate the capabilities of the proposed control framework in a series of preliminary experiments employing a 16 × 16 tactile sensor array attached to a Kuka LWR arm as a large fingertip.